bdns

Documentation

Index

• func NewStaticProvider(servers []string) (*staticProvider, error)
• func ParseTarget(target, defaultPort string) (host, port string, err error)
• func StartDynamicProvider(c *cmd.DNSProvider, refresh time.Duration, proto string) (*dynamicProvider, error)
• type Client
  • func New(readTimeout time.Duration, servers ServerProvider, stats prometheus.Registerer, ...) Client
  • func NewTest(readTimeout time.Duration, servers ServerProvider, stats prometheus.Registerer, ...) Client
• type Error
  • func (d Error) Error() string
• type MockClient
  • func (mock *MockClient) LookupCAA(_ context.Context, domain string) ([]*dns.CAA, string, ResolverAddrs, error)
  • func (mock *MockClient) LookupHost(_ context.Context, hostname string) ([]net.IP, ResolverAddrs, error)
  • func (mock *MockClient) LookupTXT(_ context.Context, hostname string) ([]string, ResolverAddrs, error)
• type ResolverAddrs
• type ServerProvider

Functions

func NewStaticProvider

func NewStaticProvider(servers []string) (*staticProvider, error)

func ParseTarget

func ParseTarget(target, defaultPort string) (host, port string, err error)

ParseTarget takes the user input target string and default port, returns formatted host and port info. If target doesn't specify a port, set the port to be the defaultPort. If target is in IPv6 format and host-name is enclosed in square brackets, brackets are stripped when setting the host.

Examples:

• target: "www.google.com" defaultPort: "443" returns host: "www.google.com", port: "443"
• target: "ipv4-host:80" defaultPort: "443" returns host: "ipv4-host", port: "80"
• target: "[ipv6-host]" defaultPort: "443" returns host: "ipv6-host", port: "443"
• target: ":80" defaultPort: "443" returns host: "localhost", port: "80"

This function is copied from: https://github.com/grpc/grpc-go/blob/master/internal/resolver/dns/dns_resolver.go It has been minimally modified to fit our code style.

func StartDynamicProvider

func StartDynamicProvider(c *cmd.DNSProvider, refresh time.Duration, proto string) (*dynamicProvider, error)

StartDynamicProvider constructs a new dynamicProvider and starts its auto-update goroutine. The auto-update process queries DNS for SRV records at refresh intervals and uses the resulting IP/port combos to populate the list returned by Addrs. The update process ignores the Priority and Weight attributes of the SRV records.

`proto` is the IP protocol (tcp or udp) to look up SRV records for.

Types

type Client

type Client interface {
	LookupTXT(context.Context, string) (txts []string, resolver ResolverAddrs, err error)
	LookupHost(context.Context, string) ([]net.IP, ResolverAddrs, error)
	LookupCAA(context.Context, string) ([]*dns.CAA, string, ResolverAddrs, error)
}

Client queries for DNS records

func New

func New(
	readTimeout time.Duration,
	servers ServerProvider,
	stats prometheus.Registerer,
	clk clock.Clock,
	maxTries int,
	log blog.Logger,
	tlsConfig *tls.Config,
) Client

New constructs a new DNS resolver object that utilizes the provided list of DNS servers for resolution.

`tlsConfig` is the configuration used for outbound DoH queries, if applicable.

func NewTest

func NewTest(
	readTimeout time.Duration,
	servers ServerProvider,
	stats prometheus.Registerer,
	clk clock.Clock,
	maxTries int,
	log blog.Logger,
	tlsConfig *tls.Config,
) Client

NewTest constructs a new DNS resolver object that utilizes the provided list of DNS servers for resolution and will allow loopback addresses. This constructor should *only* be called from tests (unit or integration).

type Error

type Error struct {
	// contains filtered or unexported fields
}

Error wraps a DNS error with various relevant information

func (Error) Error

func (d Error) Error() string

type MockClient

type MockClient struct {
	Log blog.Logger
}

MockClient is a mock

func (*MockClient) LookupCAA

func (mock *MockClient) LookupCAA(_ context.Context, domain string) ([]*dns.CAA, string, ResolverAddrs, error)

LookupCAA returns mock records for use in tests.

func (*MockClient) LookupHost

func (mock *MockClient) LookupHost(_ context.Context, hostname string) ([]net.IP, ResolverAddrs, error)

LookupHost is a mock

func (*MockClient) LookupTXT

func (mock *MockClient) LookupTXT(_ context.Context, hostname string) ([]string, ResolverAddrs, error)

LookupTXT is a mock

type ResolverAddrs

type ResolverAddrs []string

ResolverAddrs contains DNS resolver(s) that were chosen to perform a validation request or CAA recheck. A ResolverAddr will be in the form of host:port, A:host:port, or AAAA:host:port depending on which type of lookup was done.

type ServerProvider

type ServerProvider interface {
	Addrs() ([]string, error)
	Stop()
}

ServerProvider represents a type which can provide a list of addresses for the bdns to use as DNS resolvers. Different implementations may provide different strategies for providing addresses, and may provide different kinds of addresses (e.g. host:port combos vs IP addresses).